The sources of calcium for noradrenaline-induced contraction in the human thoracic internal artery.

The aim of the present study was to examine the contribution of intracellular and extracellular calcium sources in contraction caused by noradrenaline (NA) of the human internal thoracic artery (ITA) in vitro. Distal segments of ITA were obtained from 20 patients (aged 38-73, at the time of routine coronary artery surgical revascularization (CABG)). Contractile responses to 10-6 mol/L NA in the physiological salt solution and in Ca2+-free solution without and after incubation with 10-6 mol/L thapsigargin (TSG) were recorded under isometric conditions. Responses of ITA rings to 1 µM NA without incubation with TSG accounted (% of reaction to 80 mM KCl) 224.70 ± 14.06% in PSS solution, 141.30 ± 8.66% in Ca2+-free solution, and 80.03 ± 1.71% after PSS restoration and were statistically significantly different (p < 0.0001, one-way ANOVA). Responses of ITA rings to 1 µM NA with 1 µM TSG accounted (% of reaction to 80 mM KCl) 114.50 ± 2.79% in Ca2+-free solution and 36.70 ± 2.38% after PSS restoration. Responses in Ca2+-free solution and after PSS restoration without and with TSG were statistically significantly different (p = 0.0257 and p < 0.0001, respectively-t test). ITA contraction is caused by calcium derived not only from the SR and the extracellular matrix. The delivery of calcium to the space surrounding tissue does not immediately deliver calcium to the myofilaments.

Potassium induced contraction of the internal thoracic artery in vitro is time related: the potential consequences in the analysis of the mechanism of the spasm after coronary artery bypass grafting and in the analysis of the results of in vitro studies.

The aim of the present study was to examine how, under in vitro conditions, the human left internal thoracic artery (LITA) reacts to contractile agonist:potassium chloride (KCL) as a function of time, as well as to examine whether a change in the LITA reactivity can correlate with the occurrence of the refractory vascular spasm (RVS). Distal segments of LITA obtained from 33 patients aged 38-73, at the time of routine coronary artery surgical revascularization (CABG). Contractile response to 80 mmol K(+) was recorded under isometric conditions. In 16 (48,5 %) LITA segments, contractile reaction to K(+) after experiments ranging 1-10 h were registered. No contractile response even after 10 h of incubation was observed in 17 (51.5 %) LITA segments. Between 120 and 300 min after the beginning of the experiment, the reaction was maximum and amounted up to 300 % control reaction, then decreased. First, with respect to in vitro research isolated by LITA rings, while analyzing the results of the research, one should take into consideration the possibility that during the research, the functional state of the tissues changes and in particular its sensitivity to depolarization of the cell membrane. Second, the change in the sensitivity to depolarization of the cell membrane of the smooth muscles' LITA might be the potential mechanism causing the occurrence of the postoperative spasm after the CABG treatment.

[The use of echocardiography in visualisation of thoracic aorta. The role of intraoperative transoesophageal echocardiography (TEE)]. / Zastosowanie echokardiografii w obrazowaniu aorty piersiowej ze szczególnym uwzglednieniem sródoperacyjnego badania przezprzelykowego (TEE).

Transoesophageal echocardiography is an effective tool in visualisation of intrathoracic aorta. It is highly sensitive in diagnosis of aneurysms, atheromas, posttraumatic ruptures, abnormalities of aortic valve, and complications of bacterial endocarditis. It is superior to other methods in diagnosis of aortic dissection. It is rapid, cheap and can be done at the bedside. TEE is especially helpful in patients undergoing cardiac operations. It makes possible the detection of atheromatosis and assessment of plaque morphology in thoracic aorta. In cases with high risk of peripheral embolisation the surgical strategy is changed.

Levels of vitamin C In the blood plasma patients treated with coronary artery bypass grafting increases significantly after surgery.

One strong risk factor of coronary artery disease (CAD), which affects the levels of vitamin C in the blood is cigarette smoking. The supplementary effects of coronary artery bypass grafting (CABG) is smoking cessation by patients. Therefore, the aim of this study was to examine the level of vitamin C in the blood plasma one day before and one month after CABG. Human blood were collected from 20 patients (men); 1day before and 1 month after CABG. All patients were smoker and after CABG they declared their not smoking. The concentration of vitamin C in the blood plasma was assayed by FIA method with spectrophotometric detection. The mean value of the vitamin C concentration 1day before CABG was 12.36±2.84µmol/L (mean±SD), 1 month after CABG 40.07±10.95µmol/L (mean±SD). The average increase in the concentration of vitamin C was 3.27±0.73 times (mean±SD) and showed significant positive correlations (Pearson r=0.657, p=0.002). It should be consider incorporating the recommendations of preoperative smoking cessation for at least one month prior to CABG and/or additional supplementation. In addition it would be relevant to monitor the level of vitamin C in the patients' blood in the preoperative period.

Levels of l-ascorbic acid and cadmium in the saphenous vein of patients with coronary artery disease are negatively correlated.

BACKGROUND: The aim of this study was the simultaneous determination of levels of cadmium and l-ascorbic Acid (AA) in human saphenous vein (SV) used in coronary artery bypass grafting (CABG) and check whether there is a relationship between these levels. METHODS: Human SV were collected from 40 patients (20 men and 20 women; age, 40-75 years) at the time of routine coronary artery surgical revascularization. The concentration of cadmium in the tissue was determined according to the GF AAS-atomic absorption method. The concentration of AA was assayed in supernatant by FIA method with spectrophotometric detection. RESULTS: AA concentration (mean±SD); men: 98,7±13,18µg/g tissue, women: 96,06±11,98µg/g tissue. Cadmium concentration(mean±SD); men: 309±103,71ng/g tissue, women: 348,5±255,71ng/g tissue. Correlations among concentrations of AA and cadmium were insignificant negative in the group of men (Pearson r=-0,1504, p=0,5269) and in the group women (Pearson r=-0339, p=0144). CONCLUSIONS: Negative correlations among concentrations of AA and cadmium in human SV obtained in our study may indicate a protective effect of this vitamin in relation to toxic cadmium.

Influence of low molecular weight heparin preparations on human internal thoracic artery contraction.

OBJECTIVE: Low molecular weight heparins (LMWHs) offer practical and potential pharmacological advantages over unfractionated heparin in multiple applications but have not been studied as vasoactive agents. The purpose of this study was to investigate the effects of two commercial preparations of LMWHs, enoxaparin sodium and nadroparin calcium, on vasoconstriction in the human internal thoracic artery (ITA) in vitro. METHODS: Samples of redundant ITA segments obtained from 36 patients who underwent coronary artery bypass surgery were cut into 3mm wide rings and suspended in 20 ml organ bath. Activity of ITA rings precontracted with 80 mM KCl, 0.1 microM endothelin-1 (ET-1) and 1 microM norepinephrine (NE) after administration of enoxaparin and nadroparin in accumulative concentration ranging from 0.1 to 13.2 UI AXa/ml were recorded under isometric conditions by means of force transducers with digital output. The contraction after 80 mmol KCl, 0.1 microM ET-1 and 1 microM NE administration was treated as a control. RESULTS: Both studied LMWHs in concentration ranging from 0.12 to 13.2 UI AXa/ml did not change basal tonus and KCl precontracted ITA rings. When used in concentrations higher than 13.2 UI AXa/ml nadroparin but not enoxaparin significantly increased the tension in KCl precontracted arterial rings. In NE and ET-1 precontracted rings enoxaparin and nadroparin caused dose dependent relaxation without significant differences between both preparations. Incubation with nitric oxide blocker-Nomega-NITRO-L-ARGININE (L-NNA) in concentration 0.2 mM caused a significant attenuation of relaxant responses to both studied LMWHs in NE and ET-1 precontracted rings. CONCLUSION: LMWHs can have vasorelaxant effects on the receptor-mediated ITA vasoconstriction. The results suggest that LMWHs-induced relaxation in the human ITA is at least partially caused by nitric oxide release. Although the vasoactive effects are not the primary advantage of these drugs used as antithrombotics, such effects might have some clinical importance in the treatment and prophylaxis of graft spasm.

[Cadmium level in the human saphenous vein used in coronary artery bypass grafting]. / Ocena poziomu kadmu w ludzkiej zyle odpiszczelowej wielkiej uzytej w rewaskularyzacji miesnia sercowego.

The human saphenous vein is the main superficial vein of the lower limb. It begins on the foot, runs across among medial surface of shin and knee and frontal-medial surface of thigh. Saphenous vein remains the most widely used bypass conduit for the treatment of occlusive coronary and peripheral vascular disease. In vivo it exhibits rhythmic contractile activity. The cellular mechanisms controlling saphenous vein activity are poorly understood. It is likely that saphenous vein contraction is preceded by electrical activity followed by an increase in intracellular calcium. The conducted research has shown that environmental exposure to cadmium leads to an accumulation of these metals in the organism and the disturbance in the metabolism of such important elements as calcium. The objective of the present research was to describe the concentration of cadmium in human saphenous vein in vitro by atomic absorption spectrometry. An association between cigarette smoking and concentration of cadmium is reviewed.